Method of crimping textile strands



Jan. 23, 1968 c. A. Mcc 3,364,541

METHOD OF CRIMPING TEXTILE STRANDS Filed Sept. 21, 1965 2 Sheets-Sheet l Jan. 23, 1968 c;. A. MOCLUREZ 3,3

METHOD OF CRIMPING TEXTILE STRANDS Filed Sept. 21, 1965 2 Sheets-Sheet 2 United States Patent 3,364,541 METHGD 0F CRIMPING TEXTILE STRANDS Charles A. McClure, RD. 2, Malvern, Pa. 19355 Filed Sept. 21, 1965, Ser. No. 488,888 6 Claims. (Cl. 28--72) ABSTRACT OF THE DISCLOSURE This invention relates to treatment of textile strands, concerning especially strand-crimping.

The various dry methods for crimping textile strands may be classified according to whether they subject a strand to compressive, extensive, or torsional stresses to deform it from its existing, usually rectilinear configuration. Strands of synthetic resinous or linear organic polymeric composition may be drawn to increased length,

with corresponding increase in molecular orientation with respect to the longitudinal or filamentary axis of the strand during extension, for crimping purposes, with consequent detriment to crimp acceptance or retention.

A primary object of the present invention is crimping of textile strands of molecularly oriented composition without increasing their orientation with respect to the longitudinal or filamentary axis.

Another object is crimping of such textile strands under essentially tension-free conditions without compressing them longitudinally or twisting them.

A further object is provision of novel apparatus and procedure for effecting the foregoing objects.

Other objects of this invention, together with means and methods for attaining the various objects, will be apparent from the following description and the accompanying diagrams.

FIG. 1 is a side or end elevation, partially schematic, of a first embodiment of the present invention;

FIG. 2 is a front elevation, also partially schematic, of the embodiment of the preceding view, taken at IIH thereon, together with drive mechanism therefor;

FIG. 3 is a partially schematic side or end elevation of a second embodiment of this invention; and

FIG. 4 is a partially schematic front elevation of the embodiment of FIG. 3, taken at IV-IV thereon, together with heat-exchanging apparatus therefor.

FIG. 5 is a partially schematic side or end elevation of a third embodiment of the invention;

FIG. 6 is a partially schematic sectional plan of the embodiment of FIG. 5, taken at VI-VI thereon;

FIG. 7 is a side elevation, of a strand treated according to the present invention; and

FIG. 8 is a corresponding view of such a strand after heat-relaxation thereof.

In general, the objects of the present invention are accomplished, in strand-treating apparatus including a pair of counter-rotating nip rolls adapted to admit and forward a strand therebetween and means for establishing a temperature gradient across the nip from one to the other of the rolls, by means for feeding a textile strand to the surface of the cooler roll before entering the roll 3,364,541 Patented Jan. 23, 1968 nip, especially essentially tension-free. The strand being treated should have been molecularly oriented with respect to its longitudinal axis by being drawn to increased length, or otherwise, prior to treatment according to this invention.

FIG. 1 shows, viewed from the right side or end, supply package 10 from which textile strand 11 is being withdrawn by pair of nip rolls 12, 13. The strand passes directly therefrom to pair of treating nip rolls 14, 15, passing first into contact with and about part of the surface of roll 15 and then through the roll nip. After passage through this roll nip and through heater 16 the treated strand (now designated as 11) is wound up onto receiving package 20 mounted on swing arm 19 and resting on (and rotated by) drive roll 18. Traversing of the strand back and forth along the surface of the receiving package is preferred and may be accomplished by using a helically grooved self-traversing drive roll or any appropriate conventional traversing means (not shown).

FIG. 2 shows the same apparatus viewed from the front (toward the left at II-II in FIG. 1) and including drive mechanism for the various rolls, the drive mechanism having been omitted from FIG. 1 in the interest of clarity. Drive motor 21 has front shaft 22 interconnecting to the axle of feed roll 13 through gearbox 23. (Feed roll 12, which is concealed from view, may be driven in like manner by a counter-rotating shaft, not shown, from the same gearbox.) Rear shaft 26 from drive motor 21 interconnects to counter-rotating axles 28 and 29 of respective treating rolls 14 and 15 through gearbox 27. (Another shaft, not shown, from gearbox 2.7 interconnects to the ardent drive roll 18 for the age, both not visible in this view.)

Gearboxes 23 and 27 are of variable ratio type so that the speeds of rotation of the various rolls can be adjusted as desired. More particularly, they are such that the surface speed of rolls 12, 13 is at least as great as that of rolls 14., 15 so that strand 11 is fed essentially tension-free onto the surface of roll 15 in essentially nonslipping contact therewith. The strand tension imposed by rolls 12, 13 in withdrawing strand 11 from supply package 10 may be counteracted by overdriving rolls 12, 13 with respect to the speed of rolls 14, 15. .As described below, strand 11' leaving rolls 14, 15 and winding onto receiving package 20 is much shorter overall than untreated strand 11, and for this reason drive roll 18 for the receiving package is driven much more slowly than rolls 14, 15 so as to minimize winding tension and thereby avoid removing the crimp imparted to the strand according to this invention.

The speed relationships described above are greatly preferred in the practice of the present invention, in which event the molecular orientation of the strand is not in creased therein. This is not to say that separable novel features of the illustrated and described apparatus and process are unadapted to improving other apparatus or processes. In the following description the mentioned speed relationships will be assumed to exist, but without limitation thereto except as required by the context.

Rolls 14 and 15 are maintained according to this invention at dissimilar temperatures, thereby establishing a temperature gradient across the roll nip (and through the strand passing therebetween). The desired temperatures may be established by external or preferably internal heating and cooling means. Electrical heating means (not shown) for the interior of rotatable rolls is well known and may be employed to heat roll 14, while roll 15 is maintained at a suitably lower temperature by external or internal convection of cool fluid. Au economical arrangement utilizing internal convection to heat and cool the respective rolls is shown in the next pair of views.

strand-receiving pack- The roll temperatures should be controlled to ensure that the side of the strand in contact with the heated treating roll is raised to upwards of plasticization temperature but that the opposite side of the strand is maintained at a lower temperature at which the strand retains its normally elastic properties. For example, for 66 nylon satisfactory hot and cool roll temperatures are respectively on the order of a couple hundred degrees and a hundred degrees (or lower) C. Roll contact pressure, diameter, and speed also are pertinent to the actual operating temperatures of the rolls, as will be apparent to persons skilled in the arts of heat transfer and textile treatment. If the operating temperature of the heated roll is too high, or if there is an insufficient temperature differential across the roll nip between the hot and cool treating rolls, the resultant crimp will be less than that obtainable under optimum conditions. Adjustment of actual operating conditions to approach the optimum is within ordinary technical skill, especially as aided by examination of the crimp in strands treated according to this invention.

Treated strand 11' cools after passage through the treating roll nip and exhibits a generally helical configuration of crimp under essentially tension-free conditions. A further heating of the entire strand, preferably to a temperature intermediate between the respective roll temperatures (although the heater temperature may equal, or even exceed, that of the hotter roll) usually will provide a crimp increase evident as a tightening of the coiled configuration. FIGS. 7 and 8 indicate, in somewhat stylized form, the appearance of crimped strand 11 after treatment by the combination of hot and cool rolls and of further crimped strand 11 after subsequent reheating of strand 11. The heater (shown schematically as 16 in FIG. 1) may be of conductive, convective, or radiant type or may be a hybrid of two or more of the foregoing. Noncontact types of heater are preferred to avoid an ironing of strand 11 and possible reduction of the crimp on one side.

It will be understood that variations may be made in the embodiment just described without involving a departure from the inventive concept. In fact, certain modifications may be made as improvements thereto, with the object of improving the non-slipping contact of the strand with the rolls, the heating and cooling of the strand, etc. In the further embodiments described below it will be understood that the same or other suitable supply and receiving packages may be used. Of course, in any of the embodiments, the strand-treating apparatus and process may be integrated into a continuous operation from strand extrusion to fabric formation, if desired, thereby eliminating such packages.

FIG. 3 shows from the side or end, similarly to FIG. 1, a second embodiment of the invention wherein feed rolls 32, 33 correspond to feed rolls 12, 13 in the previous embodiment, and treating rolls 34, 35 correspond to treating rolls 14, 15 therein. Added roll 36 is contiguous with roll 35 and on an axis parallel to the axis of treating rolls 34, 35, forming a stack of the three rolls. In this embodiment strand 11 is shown proceeding horizontally through the nip of feed rolls 32, 33, onto the lower surface of added contiguous roll 36 and about it to the nip between roll 36 and roll 35, then through that nip and about the surface of roll 35 to the nip of the latter roll with heated treating roll 34, through the nip, and (as treated strand 11') to the windup location (not shown) after clinging to a further minor part of the surface of cool treating roll 35. This double-nip arrangement assists in ensuring essentially non-slipping contact of the strand with the cooler roll, which it reaches first, without imposing tension on the strand.

FIG. 4 shows this second embodiment viewed from the front (toward the right at IV-IV in FIG. 3) and also shows heat-exchanger 41 and interconnecting piping, which were omitted from FIG. 3 in the interest of clarity. From the heat-exchanger, pipe 44 carries heated fluid to the interior of treating roll 34, and after circulating through that hollow interior the fluid returns through pipe 48. Cooling fluid is carried from the heat-exchanger through pipe 43 and branch lines 45 and 46 therefrom to respective rolls 35 and 36, from which the fluid is returned through pipe 49 from branched outlets from these respective cool rolls. The pipes are connected to the rolls at their axes by conventional coupling seals, and when this method of temperature control is employed the drive axles of the rolls are of sleeve type, or the rolls may be surfaceor rim-driven as desired. It will be understood that the heat-exchanger conveniently contains conventional heat-transfer equipment, such as one or more compressors and expansion chambers, to establish the desired temperatures in the circulating fluid. The actual temperatures will depend on the strand composition and rate of travel, total denier and denier per filament, roll size, rate of flow and specific heat of the fluid, heat losses and other variables with which those skilled in the related arts are accustomed to deal, as suggested above.

As indicated in the drawings illustrating the first two embodiments, the treated strand is left in contact with the cooler treating roll over about a quadrant of rotation, thereby expediting the cooling of the heated portion of the strand as is conductive to crimp formation and retention. The objective of prompt and effective cooling of the strand is attained in improved fashion by a further modification, which constitutes a third embodiment of the invention.

FIG. 5 shows in side or end elevation an embodiment comprising three rolls 54, 55, and 56 stacked like rolls 34, 35, and 36 in the last previous embodiment; roll 54 is the heated treating roll, roll 55 the cooler treating roll, and roll 56 the added contiguous cool roll. Oblique pair of feed rolls 52, 53 feed untreated strand 11 to the stack of three rolls, and oblique receiving package 60 rotated by drive roll 58 removes treated strand 11' therefrom. As seen in this elevational view the strand is fed onto the lower surface of the added contiguous roll, after which it passes about it to the nipof that roll with roll 55; the strand passes completely about roll 55, passing through the nip of it with roll 54 at the midpoint, then back through the first nip (between rolls 55 and 56) in the opposite direction to its first passage therethrough; then after a further path increment to the lowest part of roll 56 the strand proceeds to windup onto receiving package 60 carried on swing arm 59.

FIG. 6 shows, with the aid of broken lines to indicate the path of the strand where hidden below one or both of rolls 55 and 56, the helical path of the strand about them, the view being taken looking downward from the nip between rolls 54 and 55. The pitch of the path angle is determined by the obliqueness of the feed and windup rolls as viewed in such a horizontal plane. It will be understood that the motive means and the temperature-control means previously illustrated and described are similarly useful here but are omitted from the views in the interest of clarity and from the description in the interest of conciseness. If desired, the added contiguous roll may be maintained at about room temperature to expedite further the cooling of the treated strand.

FIGS. 7 and 8, already mentioned in reference to the product, illustrate the generally helical configuration produced in a textile strand according to the practice of this invention. The tighter configuration of coiling in the latter view is normally attained by subsequent heat-relaxation of the just treated strand, as indicated above, regardless of which of the three embodiments is employed. It may be desirable to rub, vibrate, or otherwise separate the respective filaments of a treated multifilament strand to reduce the in-phase regularity of the coiling and thereby bulk the yarn. This may occur in conventional knitting, weaving or other fabrication steps to which such a strand normally would be subjected, or in a separate step.

Although certain embodiments of the present invention have been illustrated and described, together with mention of their respective advantages, other modifications of this invention may be made, such as substituting a twister windup instead of the illustrated simple traversewound arrangement. Moreover, if desired, parts or steps may be added, combined, or subdivided while retaining all or many of the benefits of the invention, which itself is defined in the following claims.

I claim:

1. Strand-crimping process comprising feeding a molecularly oriented textile strand of linear polymeric material over the surface of a cool roll to a treating location at the nip between the cool roll and a roll heated to plasticization temperature of the strand composition, gripping the strand momentarily on opposite sides by the rolls at the nip, heating the gripped portion of the strand on one side only to its plasticization temperature at the roll nip While maintaining the opposite side thereof at lower temperature, ungripping the heated portion of the strand and cooling it with the strand in contact with the cool roll and with another roll contiguous therewith, the other roll being unheated.

2. Strand-treating process according to claim 1, wherein the strand passes through the nip between the cool roll and the other roll.

3. In a strand-treating process in which a molecularly oriented textile strand compressing linear polymeric material is heated to substantially plasticization temperature therefor on one side and is maintained relatively cool on the opposite side by passage between a pair of nip rolls having a temperature differential across the nip from one roll to the other, the improvement comprising feeding the strand through a roll nip defined by the cooler roll and an additional roll contiguous therewith in advance of the nip between the hotter and the cooler rolls and passing the strand again through the nip defined by the cooler roll and the additional roll contiguous therewith after passage through the nip between the hotter and the cooler rolls.

4. Strand-treating process according to claim 3, wherein the additional roll is maintained at substantially room temperature.

5. In a strand-treating process in which a molecularly oriented textile strand comprising linear polymeric material is heated to substantially plasticization temperature therefor on one side and is maintained relatively cool on the opposite side by passage between a pair of nip rolls having a temperature differential across the nip from one roll to the other, the improvement comprising feeding the strand through a roll nip defined by the cooler roll and an additional roll contiguous therewith in advance of the nip between the hotter and the cooler rolls, passing the strand again through the nip defined by the cooler roll and the additional roll contiguous therewith after passage through the nip between the hotter and the cooler rolls, and passing the strand about part of the surface of the additional contiguous roll after its second passage through the nip defined by that roll and the cooler roll.

6. Strand-treating process according to claim 5, wherein the strand passes through substantially a semicircle about the additional roll.

References Cited UNITED STATES PATENTS 3,110,432 11/ 1963 Smith 26-186 X 3,111,740 11/1963 Stanley 28-1 3,113,366 12/1963 Taylor 2 81 3,167,846 2/ 1965 Iwnicki et a1 281 3,176,373 4/1965 Taylor 28-72 FOREIGN PATENTS 225,883 12/ 1959 Australia. 907,823 1 0/ 1962 Great Britain.

ROBERT R. MACKEY, Primary Examiner. 

